Area of a Triangle

Area of a Triangle

In the past, to find the area of a triangle we have used the formula

A=(1/2)bh

where b=base h=height

But, if we do not know the height of a triangle, we can use trigonometry to help us determine the area

In order to find the area of a triangle using trigonometry, we need the 2 side lengths and the angle that lies in between the two sides

Then, we can use the formula

A=(1/2)ab*sin(C)

Why does this work?

A=(1/2)bh

Example:

Fill in the Blank

Find the area of this triangle. Round to the nearest thousandths place.

.

Fill in the Blank

Find the area of this triangle. Round to the nearest thousandths place.

.

Fill in the Blank

Find the area of this triangle. Round to the nearest thousandths place.

.

Work on:

pg. 540 #4, 6, 7, 9